Semiconductor light emitting element
View Patent ↗A semiconductor light-emitting element according to the present invention includes: an n-type nitride semiconductor layer 21 ; a p-type nitride semiconductor layer 23 ; an active layer region 22 which includes an m plane nitride semiconductor layer and which is interposed between the n-type nitride semiconductor layer and the p-type nitride semiconductor layer; an n-type electrode 30 which is electrically connected to the n-type nitride semiconductor layer; a p-type electrode 40 which is electrically connected to the p-type nitride semiconductor layer; a light-emitting face, through which polarized light that has been produced in the active layer region is extracted out of this element; and a striped structure 50 which is provided for the light-emitting face and which has a plurality of projections that run substantially parallel to the a-axis direction of the m plane nitride semiconductor layer.
1. A semiconductor light-emitting diode comprising:
a substrate;
an n-type nitride semiconductor layer;
a p-type nitride semiconductor layer;
an active layer region which includes an m plane nitride semiconductor layer and which is interposed between the n-type nitride semiconductor layer and the p-type nitride semiconductor layer;
an n-type electrode which is electrically connected to the n-type nitride semiconductor layer;
a p-type electrode which is electrically connected to the p-type nitride semiconductor layer;
a light-emitting face, through which polarized light that has been produced in the active layer region is extracted out of the nitride semiconductor light-emitting element; wherein
the substrate has a first principal surface and a second principal surface;
the first principal surface of the substrate is opposite to the second principal surface of the substrate;
the n-type nitride semiconductor layer has a first surface, a second surface, and a third surface;
the third surface of the n-type nitride semiconductor layer is opposite to the first and second surfaces of the n-type nitride semiconductor layer;
the first surface of the n-type nitride semiconductor layer is in contact with the active layer region;
the second surface of the n-type nitride semiconductor layer is in contact with the n-type electrode;
the third surface of the n-type nitride semiconductor layer is in contact with the first principal surface of the substrate;
the second principal surface of the substrate is the light-emitting face;
the second principal surface of the substrate is not in contact with an electrode; and
the second principal surface of the substrate has a striped structure which is provided for the light-emitting face and which has a plurality of projections that run in a direction within ±3 degrees of the a-axis direction of the m plane nitride semiconductor layer, wherein each of the plurality of projections has at least one sloped sidewall which is not parallel to the light-emitting face.
2. The semiconductor light-emitting diode of claim 1 , wherein the plurality of projections have a period of 300 nm to 8 μm.
3. The semiconductor light-emitting diode of claim 2 , wherein the polarized light is produced in the active layer region so as to have a light distribution characteristic, of which the angle of radiation is wider in a c-axis direction than in the a-axis direction.
4. The semiconductor light-emitting diode of claim 3 , wherein the substrate is formed of GaN.
5. The semiconductor light-emitting diode of claim 1 , wherein each of the plurality of projections further comprises an end surface parallel to the light-emitting face.